I tried to check his filter rules on the bb admin service, but I ran into "The enablement process has not completed. Once complete, the redirection folders will be available." message on User / Messaging Config > Default Config / E-mail.
Apparently, the besadmin service account has insufficient privileges on the mailserver. (KB02276) Any idea how to resolve this? A way to erase all bes filters would be an acceptable quickfix at this point. 10QIA.